Data mining and knowledge extraction methods become ones of the most important issues in modern computer science. Moreover, those methods have many real-life applications, e.g. in economics, medicine, computer networks, etc. Therefore, there is a constant need for developing new knowledge representations and knowledge extraction methods. In this work a coherent survey of problems connected with relational knowledge representation and methods for achieving relational knowledge representation were presented. Proposed approach was shown on three applications: economic case, biomedical case and...